One significant oversight is stop start technology.  Overseas stop-start technology is featured on a host of models, including the Audi A3 TDI, BMW 1-Series, BMW 3-Series, Mazda 2, Mini Cooper, Toyota Yaris.  The technology is somewhat expensive -- it's about $500 extra to install -- however, it's more than worth it, providing fuel economy gains of around 7 percent.

The EPA's flawed test cycle, though, currently only includes one stop so the tech only earns automakers a 0.1 or 0.2 mpg increase in the official EPA mileage estimates, despite much larger real world gains.  Without the extra rating to justify the extra costs, manufacturers simply haven't been importing the tech on U.S. models. 

Currently, the only vehicles to feature the tech are hybrids such as the Toyota Prius, Honda Insight, Chevrolet Malibu Hybrid and BMW ActiveHybrid X6, as their electric systems allow the tech to be implemented at a much lower costs.  The net result is that at the end of the day, the U.S. is trailing the rest of the world in fuel economy.

Still the allure of models like the Volkswagen Lupo, which received an estimated 75 mpg, keep customers demanding that the EPA reconsider stop-start.  Robert Davis, Mazda's top product-development executive in North America, comments, "In Japan, we're seeing anywhere from 7 to 9 percent fuel economy gains from it. That's a jump from 33 to 37 miles per gallon in a metro environment."

Audi of America spokesman Christian Bokich complains, "We did not realize any savings in U.S. EPA estimates based on required testing cycles."

The EPA may finally be coming around and may try to fix its flawed test procedure.  It's taking public comment on stop-start technologies, currently, and will look to announce new procedures in April.  Those procedures could finally include a test with more stops.  Mazda is urging automakers to join together to lobby the EPA to give stop-start its just rewards.  While this is obviously a matter of personal interest to the company, it's also important industry wide, and to U.S. consumers.